That does not correctly state LDS doctrine. It is not revealed in LDS scripture that Peter, James, and John were the First Presidency in the early Christian church. I don’t know of any official proclamation by the Church to that effect either. Some individual authors may have speculated on that, but that was their opinions. It is not binding on the Church. Just because the Church has a First Presidency today, it does not mean that it should have had one then. The Twelve Apostles were perfectly capable of, and had the required keys to govern the church at that time without the First Presidency, as they do today.
The First Presidency is an ancient institution, and predates the the Twelve Apostles. It existed in ancient times, in the days of Adam and the ancient Patriarchs. You do not have to be an Apostle to be a member of the first Presidency. You have to be a high priest of the order of Melchizedek. The reason why they are Apostles today is because they have to rise through the ranks to get there; and rising through the ranks means being an Apostle for a period of time. It is like a stake president who has been a bishop for a time. He still remains a bishop even though he is now released from that calling and become a stake president.
Strictly speaking there aren’t 15 Apostles, but Twelve. The Twelve form a quorum whose membership cannot exceed 12. The First Presidency although they are Apostles, are not members of that quorum. They form their own quorum of the First Presidency, who function as high priests and not as Apostles. Their office of Apostle is dormant, in the same way that the office of bishop is dormant in a stake president.
Yes, which means that another member of that quorum must have died for Paul to be called to succeed him.
Those (like Barnabas) were not genuine Apostles. As you know “apostle” simply means “sent;” so anybody who is “sent” is an apostle. But he is not an Apostle in the sense of an office in the Church. It is like the word “bishop”. According to the
Online Etymology Dictionary, “bishop” means “
episcopus, from Gk.
episkopos ‘watcher, overseer,’ a title for various government officials, later taken over in a Church sense”. So you can call any “overseer” a bishop, but he is not a bishop as a church officer is a bishop. The same thing applies to those who were called apostles in the New Testament, but who were not true Apostles like Peter or Paul.
Correct.
Correct. See explanation above.
Correct; and Mormons disagree with the Catholic view.
And Apostle, meaning one of the Twelve, is an
office in the Church; in the same way that a bishop, a presbyter, or a deacon is; and therefore he has to be ordained to that office to be such.
Yes, for the same reason that the ancient church did—i.e. to act as the governing body of the whole church.
We know of at least two—Matthias and Paul. If there were more we are not informed who they were.